Beads conjugated to oligonucleotides are used in microfluidic detection applications such as high-throughput sequencing. In order to uniquely identify each partition, the beads can be labeled with unique barcode sequences. However, in order to ensure that partitions have only one bead and thus are uniquely labeled by the barcode, bead concentrations are typically adjusted so that only about 1 out of 10 partitions are occupied by a bead. This results in about 90% dead volume in the partitions, and increases the amount of sample and reagents that is needed for detection of samples.